In a large bowl, whisk 4 eggs.
Add 1 cup granulated sugar and mix well.
Add 1½ cups unsalted butter (3 sticks), room temperature, and mix until fully combined.
Stir in ½ teaspoon vanillin powder (or substitute vanilla extract) and ½ teaspoon baking soda.
Gradually add 4½ cups sifted all-purpose flour, about 1 cup at a time, mixing continuously.
The dough should be soft and workable — not sticky but not too dry. Toward the end, it may be easier to mix the dough with your hands until fully incorporated.
Divide the dough into three equal pieces.
Using a rolling pin, roll each portion of dough into a circle or rectangle, depending on the shape of your baking pan.